Preheat and prep: Heat your oven to 425°F (220°C). Line a large baking sheet with parchment paper for easy cleanup.
Lightly oil or spray the parchment to help the coating crisp.
Mix the batter: In a large bowl, whisk flour, milk, garlic powder, smoked paprika, onion powder, salt, and pepper until smooth. The mixture should resemble a thin pancake batter. Add a splash more milk if it’s too thick.
Coat the cauliflower: Place panko in a shallow bowl.
Dip each floret in the batter, let excess drip, then roll in panko to coat. Set on the prepared baking sheet, leaving space between pieces for airflow.
Bake until crisp: Lightly mist the florets with oil. Bake 20–25 minutes, flipping once at the 12-minute mark, until golden and crisp at the edges.
Make the slaw: While the cauliflower bakes, toss cabbage, cilantro, lime juice, oil, salt, and sugar in a bowl.
Let it sit to soften slightly. Taste and adjust lime or salt as needed.
Warm the tortillas: Heat tortillas in a dry skillet for 20–30 seconds per side or wrap in foil and warm in the oven for 5–7 minutes. Keep them covered so they stay soft.
Toss with BBQ sauce: In a large bowl, mix BBQ sauce with apple cider vinegar and hot sauce if using.
Add the hot cauliflower and gently toss to coat. For extra sticky edges, return the sauced florets to the baking sheet and bake 5 more minutes.
Assemble the tacos: Layer each tortilla with a spoonful of slaw, a few pieces of BBQ cauliflower, avocado, and pickled onions. Finish with cotija, jalapeño, and a squeeze of lime.
Serve right away: These are best when the cauliflower is still crisp and warm.